Systems for recuperating energy in the form of electrical energy from lower power energy sources, such as exhaust gas of domestic heating and medium sized buildings are known.
An example is disclosed in EP1221573. Thermal energy is provided by means of a burner for combustion of dry biomass, being a thermal energy source having a low power thermal energy output. The system comprises an organic Rankine cycle. In the organic Rankine cycle, thermal oil is evaporated to oil vapour, which evaporated oil is to drive a turbine in which the vapour expands. After the oil vapour is expanded, the oil vapour is condensed in a heat exchanger, being a condenser. The cold side of the condenser is water from a heating system.
Some thermal energy sources may have a large response time, and are to adjust the thermal energy output by modulating, i.e. reducing or increasing the combustion speed, rather than switching between on and off status as is frequently used for gas burners.